The present invention, in several embodiments, relates to microstrip log-periodic antennas and, more particularly, to semi-coplanar microstrip/slot log-periodic antennas and coplanar waveguide-to-microstrip line transitions.
Log-periodic antennas are typically characterized as having logarithmic-periodic, electrically conducting, elements that may receive and/or transmit communication signals where the relative dimensions of each dipole antenna element and the spacing between elements are logarithmically related to the frequency range over which the antenna operates. Log-periodic dipole antennas may be fabricated using printed circuit boards where the elements of the antenna are fabricated in, conformal to, or on, a surface layer of an insulating substrate. The antenna elements are typically formed on a common plane of a substrate such that the principal beam axis, or direction of travel for the phase centers for increasing frequency of the antenna, is in the same direction.